Effect of natural xanthophylls on growth performance and body pigmentation of yellow catfish (Pelteobagrus fulvidraco)

A 90 d experiment was conducted to investigate the effects of dietary natural lutein levels on growth,and body pigmentation of Pelteobagrus fulvidraco.Five experimental diets were designed with 0%,0.15%,0.3%,0.6% and 8% of test compound and the highest dose was ten times more than possible dose.Five extruded pellets were determined xanthophylls dosage as non detected,24.2,54.2,118 and 1700 mg/kg,respectively,which were named C,L24.2,L54.2,L118 and L1700 accordingly.Each treatment was randomly assigned four replicates with 30 fish in each tank.We found pigment inclusion did significantly enhance growth performance and feed efficiency of P.fulvidraco.Productive protein value of L24.2 group,energy productive values of L54.2,L118,L1700 groups were significantly higher than those of control group(P0.05).Yellowness(b*) and saturation(c*) of lateral and ventral skin obviously increased until they reached saturation in L118,which showed no difference with L1700 group(P0.05).Pigmentation of skin in L118 and L1700 deposited excessively and transferred into muscle.Bioaccumulation factor of skin pigment increased firstly and then decreased,the highest in fish fed 76.25 mg/kg diet.The results showed 24.2-1700 mg/kg pigment inclusion significantly improved growth performance of P.fulvidraco.The optimum concentration of pigment as a colorant in yellow catfish was 76.25 mg/kg feed.